This invention relates to the field of electrical acoustic sensory systems and more particularly to an ultrasonic proximity switch with a range selection, control and amplification circuit for use with a remotely locatable sensor.
In an existing ultrasonic proximity sensor unit (reference Distanz-Sensor Ultraschall-BERO bis lm function. Application and Design Engineering Publication No. E-733/1155) the sensor is mounted in a cubicle housing also incorporating therein both the control circuit and range selection. The operation of this known proximity unit is according to a program. Aside from the relatively large dimensions of this known ultrasonic proximity switch, the local installation requirements, e.g., minimum spacing from sidewalls, also need to be taken into account.
The object of this invention is to improve the ultrasonic proximity switch of the above-specified type so that an evaluating circuitry can be designed in a simpler and easier-to-use fashion. A further object of this invention is to provide an ultrasonic proximity switch without concerns for either spatial requirements or environmental factors, e.g., ambient temperature and correlated tolerance build-ups.